The invention relates to a method for the production of a metal-ceramic substrate or a copper-ceramic substrate and to a carrier, such as a plate shaped carrier which can be used as a production aid in this method.
A method is known for the manufacture of the metallization required for strip conductors, connectors, etc., on a ceramic, e.g. on an aluminum-oxide ceramic, using the so-called direct-bonding process and, when copper is used as the metallization, also as the DCB (direct copper bonding) process, namely using metal or copper foils or metal or copper sheets forming the metallization, the surfaces of the foils or sheets having a layer or coating (melt-on layer) consisting of a chemical bond between the metal and a reactive gas, preferably oxygen. In this method, which is described for example in U.S. Pat. No. 3,744,120 and in DE-PS 23 19 854, this layer or coating (hot-melt layer) forms a eutectic with a melting temperature below the melting temperature of the metal (e.g. copper), so that the layers can be bonded to each other by placing the foil on the ceramic and heating all layers, namely by melting the metal or copper essentially only in the area of the hot-melt layer or oxide layer.
This DCB process then comprises, for example, the following process steps:                oxidation of a copper foil so as to produce an even copper oxide layer;        placing the copper foil on the ceramic layer;        heating the composite to a process or bonding temperature between approx. 1025 and 1083° C., e.g. to approx. 1072° C.;        cooling to room temperature.        
In particular, double-sided metallized metal-ceramic substrates or copper-ceramic substrates are known, which are then manufactured using the DCB process wherein first a first copper layer is applied to a surface of a ceramic layer or a ceramic plate and then in a second step a second copper layer is applied to the other surface. The disadvantage of this is the increased complexity of the manufacturing process due to the double DCB bonding.
It is an object of the invention is to present or provide for a method that enables the manufacture of double-sided metallized metal-ceramic substrates, in particular of double-sided metallized copper-ceramic substrates, in one single processing or bonding step.